As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED AN AMBER PITCH TRIM, MACH TRIM AND AUTO PILOT PITCH TRIM CAS MESSAGES ON CLIMB TO CRUISE OUT OF CLT. CREW ELECTED TO RETURN TO CLT AND LANDED WITHOUT INCIDENT WHERE EMERGENCY EQUIPMENT DID RESPOND. MAINTENANCE REMOVED AND REPLACED THE HSTCU IN ACCORDANCE WITH THE AIRCRAFT MAINTENANCE MANUAL. AIRCRAFT WAS RELEASED FOR SERVICE.